Traditional inverter-type welding power sources often use a dual double forward, pulse width modulated (PWM), hard switching topology. One of the challenges of such a PWM method is effectively regulating low output power applications without operating the switching devices in a linear mode. Such applications typically require very short cycle on-times that are in direct conflict with the minimum on-times necessary to ensure that the switching devices operate in the full conduction mode (fully saturated), which is critical to limiting power dissipation and maximizing the life of the devices. Traditionally, a minimum cycle on-time has been used to ensure that the switching devices achieve full conduction during each cycle. However, this may result in “skip firing” at low output power levels, which is difficult to regulate and can produce undesirable audible noise.
Further limitations and disadvantages of conventional, traditional, and proposed approaches will become apparent to one of skill in the art, through comparison of such approaches with embodiments of the present invention as set forth in the remainder of the present application with reference to the drawings.